Optical imaging technologies have many attractive properties that make them ideal for investigating the lung including that they are non-destructive, are amenable to implementation using flexible small diameter fiber-optic catheters, do not require a transducing medium, and in many cases rely on endogenous contrast. Of particular interest to our laboratory is the development, use and clinical translation of optical imaging systems and techniques, particularly optical frequency domain imaging (OFDI), to address challenges in pulmonary medicine. OFDI is a second-generation optical coherence tomography imaging technology that can be used to conduct volumetric microscopy in vivo. We are currently investigating the use of OFDI for studying lung cancer, asthma, and smoke inhalation injury in ex vivo, preclinical and clinical studies.

Research Projects

The primary focus of the Pulmonary Optical Imaging Laboratory is the development and clinical translation of novel optical imaging technologies, particularly optical frequency domain imaging (OFDI), with the ultimate goal of improving patient.

Optical Coherence Tomography and Optical Frequency Domain Imaging

Optical coherence tomography (OCT) is a high-resolution optical imaging modality that provides cross-sectional images of tissue microstructure at a resolution comparable with low power bright-field microscopy (<10 µm). Optical frequency domain imaging (OFDI) is a second generation OCT technology that is capable of acquiring images at approximately 100x the speed of traditional time domain OCT systems while preserving the image quality. As OFDI is a fiber-optic imaging technology it is highly amenable to implementation through very narrow diameter, flexible catheters. With appropriate scanning techniques and the increased OFDI acquisition speeds it is therefore possible to conduct volumetric microscopy in vivo.

A large focus of our laboratory involves the development and refinement of optical frequency domain imaging (OFDI) instruments and techniques for investigating the lung. We are working towards developing new, and advancing existing, OFDI techniques for disease detection, diagnosis, and treatment, and for guiding and evaluating pulmonary interventions. In addition we are using these novel techniques to study respiratory physiology and pathophysiology including airway structure and function relationships. Examples of some of our ongoing preclinical, clinical and ex vivo imaging studies our outlined below.

We are investigating the use of OFDI for the early detection and in vivo diagnosis of lung cancer both within the conducting airway and in the peripheral lung. This multidisciplinary work involves the development and in vivo testing of novel endobronchial catheters for volumetric imaging of the airways, and transbronchial needle catheters for imaging the peripheral lung. We are currently conducting preclinical safety and feasibility studies and pilot clinical studies using the developed endobronchial and transbronchial imaging catheters. By conducting volumetric microscopy of targeted tissue regions of interest we hope to guide biopsy acquisition to the most severe pathology and therefore increase the diagnostic yield of low-risk transbronchial biopsy. We additionally anticipate that, following the development of appropriate diagnostic criteria, OFDI will enable real-time in vivo diagnosis of pulmonary pathology.

Volumetric Assessment of Pulmonary Pathology

Watch a video of OFDI imagingOFDI of airway dynamics: Cross-sectional OFDI imaging of airway dynamics in sheep. A larger lumen area is observed during an end inspiration breath hold (blue box) when compared to the same cross-sectional location and airway pressure during tidal breathing (red box). The green box indicates the same location during an end expiration breath hold. Tick marks represent 500 µm.

Accurate interpretation of in vivo OFDI images of pulmonary pathology requires the development and validation of image interpretation criteria. We are currently compiling a comprehensive library of correlated OFDI and histopathology image pairs of pulmonary pathology. This library will ultimately be used as training and testing sets for developing OFDI diagnostic criteria and will additionally be available as a reference tool. In order to ensure direct registration of the OFDI and histopathology images given the small size of non-surgical biopsy specimens, all OFDI imaging is conducted on surgical and autopsy specimens in close collaboration with the MGH pathology department.

Evaluation of the Normal and Asthmatic Airway

The long-term goal of this work is to develop a relatively non-invasive means of assessing airway inflammation, remodeling and hyperresponsiveness in vivo to increase the current understanding of the mechanisms involved in the asthmatic airway, to assess the severity of the disease in patients, and to assess the response to treatment. We are currently using OFDI, and other novel optical imaging techniques, to dynamically image the airways with sufficiently high spatial and temporal resolution to enable the real-time evaluation of the airway structure including the interaction and response of individual layers of the airway wall in both preclinical and pilot clinical studies. Information derived from these imaging studies may provide valuable insight to the complex behavior of both the normal and the asthmatic lung.

While the devastating effects of smoke inhalation injury are well documented, accurate diagnosis of patients with smoke inhalation injury remains problematic. We are therefore investigating the use of OFDI to quantify mucosal injury in preclinical animal models. OFDI metrics of smoke inhalation injury include epithelial disruption, PMN infiltrate, increased mucus production, and increased mucosal thickness. We anticipate that volumetric OFDI imaging of the airways will enable us to not only quantitatively assess the initial extent of smoke inhalation injury in patients, but will additionally facilitate monitoring the progression or healing of the injury over time, and may ultimately provide new insight into the clinical management of patients.

Research Positions

We are always looking for postdoctoral fellows with expertise in biomedical optics or pulmonary medicine. Interested applicants should send their detailed curriculum vitae, a cover letter describing relevant training and research experience, and the names and contact information of three referees to Dr. Melissa Suter.